Method For Permanently Monitoring Pressurized Pipelines and Line Systems Which Carry Fluid Media

ABSTRACT

The invention relates to a method for permanently monitoring pressurized pipelines and line systems, including connected loads, which carry fluid media, wherein pressure measurements are carried out in different modes downstream of the transfer point between the supply device and the load connection in order to determine consumption values over predeterminable periods of time and to infer the system state, said method having the following steps: an electronically controllable shut-off valve is arranged downstream of the transfer point and a pressure sensor is arranged downstream of the valve in the direction of flow; all of the removal locations are closed and pressure is built up in the system; the shut-off valve is closed and an outlet pressure drop, which may be present, is determined over a first period of time and the initial and final pressure values are stored; the valve is opened and the consumption of water with the longest equal flow rate is set and stored as the end of commissioning; a transition is made to the drawing-off mode by opening the valve over a second period of time; a changeover to the leak searching mode is made after the second period of time has elapsed by briefly closing the valve, the outlet pressure is determined and this value is stored, the pressure drop during the valve-closing procedure is calculated and is compared with a predefined fixed value; the pressure drop value from the preceding comparison step is checked and a large leak or large instantaneous consumption is determined and the result is stored in the error buffer; the pressure drop measurement is repeated within a short period of time and the pressure drop value now obtained is compared with the value in the error buffer and the error buffer is erased when no changes can be determined; a transition is made to the first stage of an extended leak searching mode, with the valve still closed, by comparing the pressure drop in this step with a predefined fixed value in order to determine a smaller leak which may be present, the error value is stored in a memory, the pressure drop measurement is repeated within a short period of time and the pressure drop now obtained is compared with the error value and the error value is erased if it is not possible to determine that the pressure drop value has been exceeded or an alarm is activated if it is determined that the value has been exceeded and a subsequent transition is made to the drawing-off mode; after the error memory has been erased, the second stage of the extended leak searching mode is begun with the valve still closed, the instantaneous outlet pressure is determined, this value is stored, a current pressure value is determined and the pressure drop which may be present is determined over a third period of time, this period of time being longer than the first or second period of time, and is compared with the outlet pressure drop determined in order to infer a minor leak if the pressure drop is exceeded; the error value is stored and reported and a transition is made to the drawing-off mode or, if the pressure drop is not exceeded, a transition is made to the rest mode with the valve closed, wherein the rest mode is ended when a current pressure measurement reveals a pressure drop or a period of time which is longer than the third period of time has elapsed, with a subsequent transition then being made to the drawing-off mode.

The invention relates to a method for permanently monitoring pressurizedpiping and line systems, including connected loads, carrying fluidmedia, with pressure measurements in different modes being carried outdownstream of the transfer point between supply device and loadconnection in order to establish consumption values over predeterminableperiods of time and to infer the system state, according to preamble ofpatent claim 1.

DE 10 2004 016 378 A1 discloses a method and an arrangement for activelymonitoring piping. The piping to be monitored carries pressurized fluidmedia, and loads are connected to the respective piping or pipingsystem.

According to the teaching already known, a continuous check or checks inpredetermined cycles is or are carried out with the aid of adifferential pressure measurement assuming two sensors, preferably atthe transfer point or downstream of the transfer point between supplydevice and load connection, to determine whether permanent and almostconstant consumption is present over a predeterminable period of time,with an abnormal state, for example a leak, being inferred in this case,and an alarm being triggered and/or the downstream piping system beingshut-off.

In the arrangement there, a series connection comprising a firstpressure sensor, a valve that can be actuated electrically orhydraulically, and a second pressure sensor is provided at the transferpoint or downstream of the transfer point between supply device and loadconnection, with control electronics being connected to the pressuresensors and the valve actuating device in order to provide an errorsignal in the case of a recognized pressure drop per unit time after acontrolled valve shut-off.

Specifically, according to DE 10 2004 016 378 A1, a valve provided atthe transfer point or downstream of the transfer point is closed duringthe leak determination operation so that the piping system locateddownstream is briefly shut off. In this state, the instantaneouslypresent inlet pressure is established and saved. After this, thepressure drop is determined on the basis of the saved inlet pressurevalue and the measured outlet pressure, and a check as to whether thedetermined pressure drop per unit time exceeds a predetermined value iscarried out, as a result of which a fault in the piping system can beinferred.

In the tapping operation, the said valve is opened and an acquisition ofchanges in the pressure differences of the pressure values upstream anddownstream of the valve is carried out. In the case of pressuredifference values no longer changing over a predetermined period oftime, a switch between the mentioned operation modes is carried out. Theswitch between leak determination operation and tapping operation ispermanently undertaken, with the switch being triggered depending onestablished pressure variations caused by consumer tap points.Generally, the switch between the individual modes is carried out anumber of times within an hour.

In the case of operation with loads which intend to continuously removemedia for a long time, e.g. for watering the garden, avolume-flow-varying element is used, with this element periodically orstochastically changing the load-dependent through-flow rate.

In the case of the method explained above, the stopping action of thevalve and also the evaluation of the pressure conditions of the inletpressure are disadvantageous for the performance aimed for. In thisrespect, the method and the associated arrangement must be optimized foreach piping structure and for specific valves, that is to say for eachdemand. Furthermore, stringent requirements are imposed on the impulsebehavior of the pressure sensors used.

With regard to known pressure difference measurements with downstreamprocessor-aided pressure evaluation, reference is also made to DE 197 06564 A1, wherein a shutting-off command is triggered in that case when apredetermined water outflow is exceeded, and there is thus no specificleak determination operation.

DE 198 14 903 C2 discloses a method for preventative shutting-off of asupply line for a medium depending on the consumption habits of theusers and pressure measurements in the lines. Specifically, the linepressure in the shut-off pipeline is measured in that case in ashut-down phase and, in the case of a pressure drop in the piping systemthat is unusual for normal consumption, a fault is signaled. In arefinement, not only the pressure drop, but also a pressure increaseover the usual level is intended to be evaluated.

In the case of this solution from the prior art, it is thus necessary toestablish pressure conditions which apply to the usual use andconsumption, with all such pressure conditions having to be saved ascomparison values.

It is thus an object of the invention to specify a method developed fromthe abovementioned for monitoring pressurized piping and line systems,including connected loads, carrying fluid media, with the methodintended to be effective in a virtually self-calibrating manner andbeing able to ensure the desired significant statements about theconditions in the piping system with a minimal number of pressuresensors. The method is intended to be able to be used both in cold waterlines and hot water lines having circulation and also to permit thedetection of so-called microleaks.

The object of the invention is achieved by a method according to thedefinition in patent claim 1, with the dependent claims at leastrepresenting expedient refinements and developments.

The fact that a repeatedly recurring pressure drop within the pipingsystem to be monitored after the supply has been cut off by closing avalve constitutes a fault is used as the approach to solve the objectaccording to the invention.

According to the invention, the arrangement of an electronicallycontrollable shut-off valve, for example a solenoid valve, downstream ofthe transfer point in connection with a single pressure sensordownstream of the valve in the flow direction is the only requirement.The method itself is implemented by control electronics, with the faultevaluation and fault processing being carried out fully automatically,that is to say aided by a program.

A piezoelectric pressure sensor with current output can be used as apressure sensor, with the shut-off valve preferably being designed as asolenoid valve with a manual override.

If an additional hot water circuit is provided in the line network, itis likewise equipped with the valve-sensor unit.

After arranging the electronically controllable shut-off valvedownstream of the transfer point and also arranging the pressure sensordownstream of the valve in the direction of flow, all removal points arefirstly closed with a resulting build-up of pressure in the system for astart-up evoked by the method. The shut-off valve is then closed, andthe outlet pressure drop present, if applicable, is determined over afirst period of time, to be precise.

Initial and final pressure values are written to a memory.

After this, the opening of the valve and setting, and also saving, ofthe water consumption with the longest unchanging flow rate are carriedout to complete the start-up procedure. This water consumption with thelongest unchanging flow rate can, for example, correspond to the fillingof a bathtub with water.

After the start-up, a transition into the tapping mode is undertaken byopening the valve for a second period of time.

After completing the tapping mode, there is a switch to the leak searchmode, to be precise after the second period of time has elapsed, that isto say the period of time corresponding to the tapping mode, by brieflyshutting off the valve, determining the outlet pressure and saving thisvalue, calculating the pressure drop during the procedure to close thevalve and comparing it to a predetermined fixed value.

After this, checking the value of the pressure drop in the precedingcomparison step and determining a large leak or high instantaneousconsumption, as well as writing the result to the error buffer areimplemented.

This pressure drop measurement is repeated within a relatively shortperiod of time and a comparison of the value of the pressure dropobtained at this point in time to the value in the error buffer iscarried out, and the error buffer is erased if no change can bedetermined.

After this step, a transition into the first stage of an extended leaksearch mode with the valve still being closed is undertaken by comparingthe pressure drop in this step with a predetermined fixed value fordetermining a smaller leak that could be present. This error value islikewise written to a memory, and a repetition of the pressure dropmeasurement is carried out within a short period of time and acomparison of the value of the pressure drop obtained at this point intime to the error value is carried out, and the error value in thememory is deleted if no excess of the pressure drop value can bedetermined, or an alarm is emitted if it is determined that the value isexceeded, with a subsequent transition into the tapping mode.

After deleting the error value, a second stage of the extended leaksearch mode is initiated, with the valve still being closed. In thiscase, the instantaneous outlet pressure is established, the outletpressure value is saved, establishing a current pressure value anddetermining the pressure drop present, if applicable, over a thirdperiod of time which is longer than the first or second period of timeare carried out, and a comparison with the established outlet pressuredrop is carried out, in order to infer a small leak if it is exceeded.

The error value is then saved and reported, and a transition into thetapping mode is carried out, or, in the case of not exceeding thepressure drop, a transition into the rest mode with the valve closed iscarried out, with the rest mode ending when a running pressuremeasurement reveals a pressure drop or a period of time has elapsedwhich is greater than the third period of time, with a transition intothe tapping mode following in turn.

According to the invention, there is permanent switching between tappingand leak modes, and rest mode.

In a refinement, in the case of multiple terminations of the leak searchwith an error message, the summed up error value is compared to a presetvalue and, in the case of it exceeding the preset value, a significantsystem fault with a large leak is inferred.

In the case of multiple terminations of the extended leak search with anerror message, the summed up error value is compared to a second presetvalue and, in the case of it exceeding this preset value, a smaller leakin the system is recognized.

According to appropriate specifications, in the case of a fault thevalve is permanently closed.

In the case of arranging the valve-sensor unit upstream of a filter unitor pressure control unit in the flow direction, it is possible for thevalve-sensor unit to detect mains-side pressure excesses and, ifapplicable, the connected piping system can be protected against thesepressures by closing the valve.

Additional temperature sensors and their measured values permit therecognition of pressure variations on account of temperature changes inthe medium, and the elimination of these during the search for thefault.

The invention is intended to be explained in more detail below on thebasis of an exemplary embodiment with reference to the flowcharts.

The flowcharts show the different modes of operation of the methodaccording to the invention, with sensor B being understood to mean thesensor in the cold water line, and sensor A meaning the sensor in thehot water line.

The start-up is carried out after switching-on the hardware-implementedmeasuring apparatus by means of the user firstly being prompted to bleedthe system. Then all water removal points are to be closed. It is thenpossible to check the tightness of the respective piping system. Thisstart-up step can be skipped if the system does not have any leaks.

To check for tightness, the preferably used solenoid valve is closed andthe minimal pressure drop over a fixed period of time, for example 150seconds, is established. A minimal pressure drop can be caused, forexample, by dripping faucets or toilet tanks.

Likewise, the tightness of the hot water system is checked at theoperating point, but of course only if such a hot water system ispresent and the sensor system is installed in it.

To check the hot water system, the solenoid valve in the hot water partis closed and the pressure drop is established over a fixed period oftime. By way of example, a pressure drop here can be traced to a coolingof the water due to interrupted circulation.

Finally, the prompt to set the water consumption with the longest flowrate is carried out, for example to fill a bathtub.

The following description of the function relates to the cold water partof the piping installation to be monitored, unless specificallymentioned otherwise.

The operation evoked by the method relating to the hot water part of theinstallation is only explained separately in the extended leak searchmode, part 2, and in the error evaluation part. In all other modes, thehot water valve is opened and the pressure sensor only serves fordetermining the instantaneous pressure.

In the tapping mode, the valve is opened for a specified period of time,for example for 60 seconds. Afterward the system switches into the leaksearch mode.

The leak search mode is initiated by shutting-off the water supply bymeans of the solenoid valve and the instantaneous outlet pressure issaved.

During the closing of the valve, the pressure drop, calculated by thesaved outlet pressure and the currently measured outlet pressure, iscompared to a fixed value, for example 150 mbar.

Should this pressure drop be exceeded, there is either a large leak inthe system, or a load requires water from a tapping point at this momentin time.

The obtained result is written to an error memory as a possible majorfault of the monitored system, and the system transitions back to thetapping mode.

However, should the pressure drop not be exceeded within a set, shortperiod of time, for example 3 seconds, then a correct state isdetermined, the error memory is erased, and the system transitions intothe extended leak search operation, part 1.

In the case of the extended leak search operation or leak search mode,part 1, the valve continues to remain closed and the pressure drop,calculated by the saved outlet pressure and the currently measuredoutlet pressure, is compared to a fixed value, for example 150 mbar.

Should this pressure drop be exceeded, there is either a small leak inthe system, or a load requires water from a tapping point.

The obtained result is written to the error memory as a possible smallfault of the monitored system, and a transition to the tapping mode iscarried out.

Should the pressure drop not be exceeded within a set period of time,for example 30 seconds, then a correct state is determined, the errormemory state is erased, and the system transitions into the extendedleak search operation, part 2.

The abovementioned mode is used to eliminate the adjusting or closingproperties of the valve and possible fluid turbulence for followingmeasurement steps and their evaluation.

In the case of the extended leak search mode, part 2, the valvecontinues to remain closed and the instantaneous outlet pressure issaved.

In addition, the hot water valve, if present, is closed and theinstantaneous outlet pressure is likewise saved.

The pressure drop, calculated from the outlet pressure that has justbeen saved and the currently measured outlet pressure, is compared tothe minimal pressure drop per unit time (which is set during thestart-up, to be precise after the tightness measurement for the coldwater part and hot water part).

Should this pressure drop be exceeded, in either the cold water part orthe hot water part to be precise, then there is either a small leak inthe system, or a load requires water.

If the pressure drop in the cold water part is negative, that is to sayif pressure is building up, for example −50 mbar, then the measurementis not successfully completed and it is repeated.

The recognized results are written as a possible small error of themonitored system into the error memory, separately for cold water andhot water to be precise, and the system transitions back into thetapping mode.

If the pressure drop for the hot water part at the operating point isnot exceeded within a set period of time, for example 10 seconds, thenthe hot water supply system should be considered to be in order, theerror memory state for hot water is deleted and the hot water valve isreopened.

If the pressure drop in the cold water part is not exceeded within a setperiod of time, for example 150 seconds, then the state that is in orderis determined, the error memory state is deleted and the systemtransitions into the rest mode.

The valve continues to remain closed in the rest mode, and the pressuredrop, calculated from the saved outlet pressure and the currentlymeasured outlet pressure, is compared to a fixed value, for example 150mbar.

If this pressure drop is exceeded or a period of time of approximately30 minutes has run out, the system is transferred into the tapping mode.

Involved with the evaluation, there is thus permanent switching betweenthe tapping mode, the various leak search modes and the rest mode duringnormal operation. However, this is not noticeable for the user, sincethe switching is very rapid and the pressure drops during the switchingon and off are particularly small.

The updated state of the system to be monitored is always available inthe error memories.

Should the leak search have been repeatedly completed with an errorresult and the summed up error value exceed a set value, a large faultcan be assumed to be within the monitored system.

Should the extended leak search have been repeatedly completed with anerror result and the summed up error value exceed a set value, a smallleakage can be assumed to exist within the monitored system.

In the case of a fault, the solenoid valves for cold water, and possiblyalso for hot water, are permanently closed, or an alarm is output,depending on what was preset. The alarm message can be forwarded to abase by telephone, text message (SMS), or radio signal.

In the case of one embodiment of the invention, the valve-sensor unit islocated either upstream or downstream in flow direction of a filter or apressure control unit, depending on the construction of the pipingnetwork. If the system is installed upstream of the filter/controller,it is possible to detect mains-side pressure excesses and to protect thepiping by shutting it off.

If the system is installed downstream of the filter/controller, it canmonitor its functioning and likewise protect the piping by shutting itoff.

By means of the installed counter for negative pressure differences inthe extended leak search mode, part 2, the state of a check valve of ahot water processing system, for example, can be established.

The breakdown of the hot water processing system with regard to thedesired heating of the water can be detected without temperature sensorsin for example 10 seconds, by means of the permanently too low pressuredrop during the tightness measurement in the case of the extended leaksearch, part 2, hot water since the cooling curve is much flatter in thecase of lower fluid temperatures.

In a refinement according to the invention, it is possible to providefor a plurality of valve-sensor units in part lines of a pipe system, sothat an occurrence of a fault can easily be limited spatially.

By means of additional temperature sensors, the accuracy in the case oflarge and/or rapid temperature variations of the fluid medium canfurthermore be improved.

It is in principle possible to arrange the pressure sensor at variouslocations downstream of the valve. The pressure measurement of the fluidcan also be determined indirectly, via pressure compensation vessels forexample, or by other means present in the system. Of course it ispossible to provide the system and its hardware and software with anintegrated current supply which ensures that the memory is saved oroperation continues in the case of a power failure.

The invention thus permits permanent monitoring of piping and pipingsystems with regard to leakages of different types. Alternatively, atemporary check is possible by installing a corresponding sensor systemas a mobile machine and the connected piping system being analyzed overa predetermined period of time. With regard to the pressure measurementsin the cold water line and/or hot water line, the function of valvespresent, check valves for example, can be checked by means of aspecification of the system software.

There is additionally the possibility of determining heat losses of thepiping system carrying the fluid media by means of evaluating measuredpressure and temperature curves, in the case of a temperature sensorsystem being present. Finally, it is possible, according to theinvention, to undertake time-controlled quantity limitation of theinflow of fluid media via particular piping or piping branches by usingan apparatus required to implement the method. In addition to thecontrol functions described above, it is within the scope of theinvention to use the saved data and error states for the purpose ofdocumenting conditions in the piping system, for example for controllingrequired heating-up functions of hot water processing systems for thepurpose of reducing germs.

1. A method for permanently monitoring pressurized piping and linesystems, including connected loads, carrying fluid media, with pressuremeasurements in different modes being carried out downstream of thetransfer point between supply device and load connection in order toestablish consumption values over predeterminable periods of time and toinfer the system state, characterized by the following steps: arrangingan electronically controllable shut-off valve downstream of the transferpoint and a pressure sensor downstream of the valve in the direction offlow; closing all removal points and building pressure in the system;closing the shut-off valve and, if applicable, determining an outletpressure drop present over a first period of time, saving the initialand final pressure values; opening the valve and setting, and alsosaving, the water consumption with the longest unchanging flow rate tocomplete the start-up procedure; transitioning into the tapping mode byopening the valve for a second period of time; switching to the leaksearch mode after the second period of time has elapsed by brieflyshutting-off the valve, determining the outlet pressure and saving thisvalue, calculating the pressure drop during the procedure to close thevalve and comparing it to a predetermined fixed value; checking thevalue of the pressure drop in the preceding comparison step anddetermining a large leak or high instantaneous consumption and writingthe result to the error buffer; repeating the pressure drop measurementwithin a short period of time and comparing the value of the pressuredrop obtained at this point in time to the value in the error buffer,and deleting the error buffer if no change can be determined;transitioning into the first stage of an extended leak search mode withthe valve still being closed by comparing the pressure drop in this stepto a predetermined fixed value for determining a smaller leak that couldbe present, writing the error value to a memory, repeating the pressuredrop measurement within a short period of time and comparing the valueof the pressure drop obtained at this point in time to the error value,and deleting the error value if no excess of the pressure drop value canbe determined, or emitting an alarm if an excess value is determinedwith a subsequent transition into the tapping mode; initializing thesecond stage of the extended leak search mode after erasing the errormemory with the valve still being closed, establishing the instantaneousoutlet pressure, saving this value, establishing a current pressurevalue and also, if applicable, determining the pressure drop presentover a third period of time, this period of time being longer than thefirst or second period of time, and comparison to the established outletpressure drop, in order to infer a small leakage in the case of excess;saving and reporting the error value and also transition into thetapping mode or, in the case of the pressure drop not being exceeded,transition into the rest mode with a closed valve, with the rest modebeing terminated when a running pressure measurement reveals a pressuredrop, or a period of time has elapsed, which is longer than the thirdperiod of time, with a subsequent transition into the tapping mode. 2.The method as claimed in claim 1, characterized by permanent switchingbetween tapping and leak search modes, and rest mode.
 3. The method asclaimed in claim 1 or 2, characterized in that, in the case of multipleterminations of the leak search with an error message, the summed uperror value is compared to a preset value and, in the case of itexceeding the preset value, a significant system fault with a large leakis inferred.
 4. The method as claimed in one of the preceding claims,characterized in that, in the case of multiple terminations of theextended leak search with an error message, the summed up error value iscompared to a further preset value and, in the case of it exceeding thisfurther preset value, a smaller leak in the system is inferred.
 5. Themethod as claimed in claim 3 or 4, characterized in that, according tospecifications, in the case of a fault the valve is permanently closed.6. The method as claimed in one of the preceding claims, characterizedin that in the case of arranging the valve-sensor unit upstream in theflow direction of a filter unit or pressure control unit, thevalve-sensor unit detects mains-side pressure excesses and, ifapplicable, the connected piping system is protected against thesepressures by closing the valve.
 7. The method as claimed in one of thepreceding claims, characterized in that pressure variations due totemperature changes of the medium are taken into account via additionaltemperature sensors.
 8. The method as claimed in one of the precedingclaims, characterized in that the valve-sensor unit is additionally usedin a hot-water line that is present.
 9. The method as claimed in claim8, characterized in that the valve in the hot-water line is closed atthe beginning of the second stage of the extended leak search mode andthe measurement and evaluation mode related to this is initiated.